# What is the frequency of f(t)= sin 3 t - cos 10 t ?

$2 \pi$
Period of sin 3t --> $\frac{2 \pi}{3}$
Period of cos 10t --> $\frac{2 \pi}{10} = \frac{\pi}{5}$
Least common multiple of $\frac{2 \pi}{3} \mathmr{and} \frac{\pi}{5}$ is $2 \pi$
Period of f(t) --> $2 \pi$